The yeast Candida albicans is a normal resident of the human digestive tract. It is also the most common fungal pathogen of humans, causing both mucosal and systemic infections, particularly in immune compromised patients. This proposal seeks to understand how C. albicans orchestrates its many interactions with the host. Our strategy is to approach aspects of commensalism and pathogenicity through dissection of the transcriptional circuitry that controls these processes. Our overarching goal is to understand how C. albicans is specialized to thrive and cause disease in many different environments of the host. PUBLIC HEALTH RELEVANCE: C. albicans is the most prevalent fungal pathogen of humans. It causes superficial infections in normal humans and life threatening, systemic infections in immune compromised individuals. This proposal seeks to understand how C. albicans regulates its genes so it can survive and proliferate in many environments of its human host. An important component of our work is the identification of virulence genes which, in the long term, will provide molecular targets for new classes of antifungal drugs.